🌿 Folk Prescriptions

The angle, direction, and depth of needle insertion refer to specific operational requirements after the fine needle is inserted beneath the skin. Correctly mastering these aspects during acupuncture is crucial for obtaining needle sensation, performing tonification and sedation, achieving therapeutic effects, improving treatment outcomes, and preventing accidental complications. Proper point selection involves not only correct surface positioning but also combining it with appropriate needle angle, direction, and depth to fully activate the therapeutic potential of acupoints.
Therefore, acupoints should not be viewed simply as small dots but as three-dimensional structures. Clinically, even the same acupoint may yield different results depending on variations in angle, direction, and depth—different tissues are reached, varying sensations arise, and treatment outcomes differ. For clinicians, proficiency in needle manipulation is closely tied to their ability to properly control angle, direction, and depth. The actual choice of angle, direction, and depth depends on the site, treatment needs, and individual patient factors such as physique and body shape.
I. Needle Insertion Angle: The angle refers to the angle formed between the needle shaft and the skin surface. Its size varies according to the acupoint location, nature of the disease, and required technique. Generally, angles fall into three categories: vertical, oblique, and horizontal.
1. Vertical Insertion: The needle shaft forms a 90° angle with the skin surface, inserted vertically into the acupoint. This method suits most acupoints, especially those over thick muscles.
2. Oblique Insertion: The needle shaft forms approximately a 45° angle with the skin surface, inserted at an incline into the acupoint. This method is suitable for shallow skin areas, regions containing vital organs, or acupoints unsuitable for deep vertical insertion, particularly in joint areas. It is also commonly used when applying certain Qi-moving or Qi-regulating techniques.
3. Horizontal Insertion (also called transverse or subcutaneous insertion): The needle shaft forms about a 15° angle with the skin surface, inserted horizontally into the acupoint. This method is ideal for acupoints located in thin skin and minimal flesh, such as those on the scalp, face, sternum, and techniques like trans-acupoint insertion, scalp acupuncture, and wrist-ankle acupuncture.
II. Needle Direction: Refers to the orientation of the needle tip during insertion and afterward—commonly called "needle direction." Direction generally follows the course of the meridian, acupoint distribution, and target tissue structure. While related to angle (e.g., facial acupoints often use horizontal insertion, neck and throat acupoints use transverse insertion, mid-chest acupoints use horizontal insertion, lateral chest acupoints use oblique insertion, abdominal acupoints use vertical insertion, back and waist acupoints use oblique or vertical insertion, and limb acupoints generally use vertical insertion), the angle primarily depends on anatomical characteristics of the site, whereas direction is determined by specific therapeutic needs. For example, regarding the Jiaochē point: when treating mandibular disorders, cheek pain, or locked jaw, insert the needle obliquely toward the temporal region so that the sensation radiates throughout the cheek; when treating facial paralysis or facial deviation, insert horizontally toward the mouth corner; when treating mumps, insert obliquely toward the parotid gland; but when treating toothache, insert vertically.
III. Needle Depth: Refers to how deeply the needle penetrates the skin and flesh of the acupoint. Depth must ensure a sensation of Qi arrival without damaging underlying tissues or organs. In clinical practice, proper depth considers multiple factors: patient age, constitution, condition, acupoint location, depth of meridian pathways, seasonal changes, practitioner experience, and need for Qi sensation. As *Suwen·Zhi Yao Lun* states: "Needle depth varies, each according to its principle... improper depth becomes a great harm," emphasizing the necessity of appropriate depth. To correctly determine depth, consider the following:
1. Age: *Lingshu·Ni Shun Fei Shou* says: "For infants and thin individuals, insert shallowly and quickly; for robust, heavy individuals, insert deeply and leave longer." Elderly or weak individuals with depleted qi and blood, and children with delicate constitutions, should avoid deep insertion. Young adults with strong qi and blood may tolerate deeper insertion.
2. Body Type: Patients vary in build—fat or thin, strong or weak. *Suwen·San Bu Jiu Hou Lun* states: "First assess the patient’s body type to adjust qi deficiency or excess." Zhang Zhicong adds: "Knowing body type determines needle depth." Thus, thinner, weaker individuals require shallower insertion; fatter, stronger individuals may tolerate deeper insertion.
3. Location: Acupoints on the head, face, and back should be inserted shallowly; acupoints on limbs and buttocks may be inserted more deeply.
4. Meridians: Meridians vary in depth and nature—yin or yang. Ancient texts suggest deeper insertion for deeper meridians, shallower for superficial ones; yang meridians (superficial) should be shallowly inserted, yin meridians (deep) deeply inserted. As *Lingshu·Yin Yang Qing Zhuo* states: "For yin meridians, insert deeply and retain; for yang meridians, insert shallowly and quickly." Generally, meridians running through elbows, arms, knees, and legs are deeper, requiring deeper insertion; those on wrists, ankles, fingers, and toes are shallower, requiring shallower insertion.
5. Condition: *Lingshu·Wei Qi Shi Chang* states: "Diseases vary in depth and location—cannot be fully enumerated. Each has its own place. Mild cases require shallow insertion, severe cases deep insertion; minor cases use fewer needles, major cases more needles—adjust treatment accordingly." *Lingshu·Zhong Shi* adds: "For full pulses, deep insertion to release qi; for empty pulses, shallow insertion to preserve essence and avoid depleting the pulse, while eliminating pathogenic factors." This indicates that insertion depth must be tailored to disease nature and mechanism.
6. Technique: *Yixue Rumen* states: "Tonification draws qi from the defensive layer—use light, shallow insertion, following the defensive qi to replenish deficiency; sedation discards qi from the nutritive layer—use heavy, deep insertion, intercepting the nutritive qi to remove excess." *Nanjing* notes: "Needling the nutritive layer must not injure the defensive layer; needling the defensive layer must not injure the nutritive layer"—emphasizing that depth must be carefully considered and targeted. If deep insertion is needed but shallow is used, the nutritive layer is missed while the defensive layer is damaged; if shallow insertion is needed but deep is used, excessive damage occurs, harming the nutritive layer.
7. Seasonal Timing: Human physiology aligns with seasonal changes. Acupuncture must adapt to seasons. *Suwen·Zhen Yao Jing Zhong Lun* says: "Spring, summer, autumn, winter each have their own rules." Depth must consider both condition and season. *Lingshu·Ben Shu* states: "In spring, target collateral vessels, Luo points, and major channels in the intermuscular spaces; for severe cases, insert deeply; for mild cases, insert shallowly. In summer, target all transport points, collateral vessels, muscles, and skin. In autumn, target convergence points, following spring methods. In winter, target well points and transport points in the inter-channel spaces, insert deeply and retain." Generally, shallow insertion is preferred in spring and summer, deep insertion in autumn and winter—based on *Nanjing*'s principle: "In spring and summer, yang energy rises to the surface, and human qi also ascends, so shallow insertion is appropriate; in autumn and winter, yang energy descends, and human qi also sinks, so deep insertion is suitable." Ignoring seasonal timing leads to serious consequences, as *Suwen·Si Shi Ci Ni Cong Lun* warns: "All four-season acupuncture must follow the natural order. Deviation causes internal chaos and disease."
8. Needle Sensation: For patients with strong, fast-onset soreness, numbness, distension, or heaviness upon needling, or those anxious and fearful of needles, shallow insertion is advisable. For those with delayed or weak sensations, deeper insertion is preferable. As *Zhenjiu Dacheng* states: "Depth and shallowness depend on the sensation—stop when Qi arrives"—meaning depth should be guided by the sensation of Qi arrival. The angle, direction, and depth of needle insertion are inseparable. Generally, deep insertion uses vertical technique, shallow insertion uses oblique or horizontal techniques. For acupoints near the medulla oblongata, eyes, chest, abdomen, and back, where vital organs lie nearby, precise control of angle, direction, and depth is essential to prevent accidental complications.